Protein Family Models

Biotin synthase (BioB), EC:2.8.1.6 , catalyses the last step of the biotin biosynthetic pathway. The reaction consists in the introduction of a sulphur atom into dethiobiotin. BioB functions as a homodimer [1]. Thiamin synthesis if a complex process involving at least six gene products (ThiFSGH, ThiI and ThiJ). Two of the proteins required for the biosynthesis of the thiazole moiety of thiamine (vitamin B(1)) are ThiG and ThiH (this family) and form a heterodimer[2]. Both of these reactions are thought of involve the binding of co-factors, and both function as dimers [1,2]. This domain therefore may be involved in co-factor binding or dimerisation (Finn, RD personal observation). [1]. 12482614. The PLP-dependent biotin synthase from Escherichia coli: mechanistic studies. Ollagnier-de-Choudens S, Mulliez E, Fontecave M;. FEBS Lett 2002;532:465-468. [2]. 12650933. Thiamine biosynthesis in Escherichia coli: isolation and initial characterisation of the ThiGH complex. Leonardi R, Fairhurst SA, Kriek M, Lowe DJ, Roach PL;. FEBS Lett 2003;539:95-99. (from Pfam)

Date:

2024-10-16

Radical SAM proteins catalyse diverse reactions, including unusual methylations, isomerisation, sulphur insertion, ring formation, anaerobic oxidation and protein radical formation. [1]. 11222759. Radical SAM, a novel protein superfamily linking unresolved steps in familiar biosynthetic pathways with radical mechanisms: functional characterization using new analysis and information visualization methods. Sofia HJ, Chen G, Hetzler BG, Reyes-Spindola JF, Miller NE;. Nucleic Acids Res 2001;29:1097-1106. [2]. 17335281. Anaerobic sulfatase-maturating enzymes: radical SAM enzymes able to catalyze in vitro sulfatase post-translational modification. Benjdia A, Leprince J, Guillot A, Vaudry H, Rabot S, Berteau O;. J Am Chem Soc. 2007;129:3462-3463. [3]. 16766528. A new type of bacterial sulfatase reveals a novel maturation pathway in prokaryotes. Berteau O, Guillot A, Benjdia A, Rabot S;. J Biol Chem. 2006;281:22464-22470. (from Pfam)

Date:

2024-10-16

ThiH, a radical SAM enzyme involved in thiamine biosynthesis, acts on L-tyrosine and produces 2-iminoacetate. An alternate pathway for biosynthesis of the intermediate hydroxyethylthiazole relies instead on ThiO starting with glycine. Other proteins involved in hydroxyethylthiazole biosynthesis include ThiF, ThiS, and ThiG.

Gene:

thiH

Date:

2024-05-30